Singing rotors

[karlp]

And a fairly comforting tone.
I just replaced both front rotors, wheel bearings and pads. I am missing the pad spreader spring on one side. Now the rotor sings with the brakes off. Goes away when I lightly brake. Gets worse as the brakes heat up.
I checked bearings for play, pads for being there, and pins. All looks O.K.
Should I try to find a pad spreader spring? Maybe it will go away as the pads set in?

Thanks, Karl P

[Joe Ricard]

Karl, did you use some of that blue disk brake adhesive stuff? I always glue the pad to the piston so that the pad gets puller away from the rotor as you let up on the pedal.
The way I understand it is as you let up on the pedal, the piston seal returns to it's original shape which pulls on the piston ever so slightlyback into the cylinder bore. When the seals get old they lose thier elasticity and don't retract as good. Plus you most likely had to push the pistons back in so now the seal is set on a different spot on the piston.
By the way the missing spring thing could do it also as it helps keep the pad square. The squeal is more of a high frequency vibration.

[karlp]

I did not use anything between the piston and pad. I've never believed that stuff can survive very long in the heat they see, any way. Could be way wrong, though. Any idea where I can get the hardware kit, or just a spring thing? PP does not seem to carry them.
How is yours coming? Last I saw was a washer disappeared on you during assembly, and then showed up in a bad spot later.

Karl P.

[Joe Ricard]

Scored a super special deal on some U.S. pistons and cylinders. Then TIG welded up the head combustion chamber. Goes like stink.
Just so happens I am playing with brakes right now. I have some "M" calipers I want to put on the front. Heard I can remove the spacer and get it to fit. Bigger piston etc. Although I think I will have to use the 914/4 spring thingy, bolts and pins. I will look in my parts boxes tonight.